When Tigers right fielder Nick Castellanos texted former teammate Justin Verlander last week, it wasn’t to congratulate him over his recent shutout of the Los Angeles Angels or his league-leading ERA, nor to relive fond memories from when Verlander was still pitching in Detroit.

Castellanos sent the former Tigers ace a text message after hearing about the Supreme Court decision last Tuesday, a landmark case which paves the way to allow legalized betting on professional sports in all states. This was not some abstract legal precedent that went unnoticed, but a decision with real, tangible effects on the future of Major League Baseball and its players.

Both Castellanos, who is the Tigers union rep to the MLB Players Association, and Verlander, who has long been vocal in advocating for players on some critical issues, knew this could have potentially huge implications.

Considering the shifting attitudes about betting over the last decade, particularly with the...